Despite what you think sir, fanfiction isn't cancer. Tell me. What is so bad about someone writing a story about already existing characters? Reading is reading, it doesn't matter what form it's in as long as you enjoy it.

Well, despite what media would have you think, there's nothing wrong with reading fanfiction. Keep doing that if you want, but I'm sure there are other reasons you'd like to change, I won't push. Otherwise, take the great advice, and I suppose I'd offer my own. Since it's fanfiction, there's obviously source material that it's based on. Maybe try to find some books with similar themes to the source material for the fanfiction you read.